import java.util.Scanner;

public class ifcome3 {
    public static void main(String[] args) {

        Scanner scanner=new Scanner(System.in);
        System.out.println("请输入成绩");
        int gride=scanner.nextInt();
        if(gride>90) {
            System.out.println("A");
        } else if (gride>80) {
            System.out.println("B");
        } else if (gride>70) {
            System.out.println("C");
        } else if (gride>60) {
            System.out.println("d");
        }
        else {
            System.out.println("E");
        }
    }
}
